This project seeks to employ mobile heath (mHealth) technologies to reduce the spread of HIV among gay, bisexual, and other men who have sex with men (MSM) in the Central Eastern European country of Romania. Rampant stigma contributes to the increasing prevalence of HIV among Romanian MSM and drives a lack of access to MSM-friendly HIV prevention services. While our established internet-based chat intervention circumvents barriers to access and supports health in stigmatizing contexts, we will translate it to a fully mobile platform and incorporate local cultural needs to ensure feasibility and appeal, and maximize efficacy among Romanian MSM. Delivering an innovative live chat counseling program alongside real-time risk behavior tracking on mobile devices can curb the increasing prevalence of HIV among Romanian MSM. In Aim 1 (months 1-6), we will conduct interviews with 5 key community informants and 15 MSM to guide us in assessing local HIV prevention needs and adapting MiCHAT for cultural resonance. Next, we will adapt the intervention with our Romanian collaborators. In Aim 2 (months 4-8), we will develop implementation protocols with intervention site staff and train three counselors. We will also work with our technical software developer, Data Center Solutions (DCS), to translate the intervention tools for mHealth delivery (smartphone chat intervention platform and real-time behavioral tracking tools). In Aim 3 (months 9-24), we will test the feasibility and acceptability f this mHealth intervention by delivering it to 40 high-risk MSM. Participants will be assessed (a) at baseline, (b) throughout the intervention using behavioral tracking software, and (c) at 6 months follow- up for risk (e.g., UAI) and protective (e.g., HIV testing, knowledge) patterns, and intervention acceptability. Collaborative review of findings will enable future mHealth research and preparation for an RCT. This pilot examines the feasibility of harnessing mHealth potential to build local capacity for the dissemination of an adapted online intervention to efficiently reac vulnerable MSM. If proven feasible, acceptable, and preliminarily efficacious in this pilot trial, this development project will mark the beginning of a program of applied mHealth research and practice for efficacy and effectiveness trials in other geographic locales where MSM are disproportionately affected by HIV and underserved by standard prevention approaches. Lastly, this unique research opportunity will foster the PIs' expertise in international research and provide an ideal context to apply their local US research knowledge globally.